It is well known that a TW electroerosion machine is highly suitable for imparting an intricate contour with high machining accuracy to a workpiece, and thus for producing, e.g. dies and molds with severe tolerance requirements. These products have their own particular specifications as demanded to meet their own particular purposes so that each must be prepared from a relative expensive blank workpieces and yet be machined individually with an extremely high degree of machining precision.
While a TW electroerosion machine, especially when designed to operate under numerical control, has proven capable of machining such a contour even of highly complex geometry with precision automatically and more efficiently than any other conventional machine, it has been found that the existing TW machine requires skillful attendance by the operator to the machine before and after the machining is carried out in the machine, and is far less than inefficient where a variety of contoured products are to be consecutively manufactured from different workpiece blanks. Such blanks require not only different machining programs but different attendant operations with respect to both work handling and machine setting. In addition, a peculiarity of the TW process has required of each separate and independent blank workpiece a start hole to allow threading by a wire electrode to initiate electroerosion. As the machining contour differs from one workpiece to another, the start hole differs in position and requires separate positioning programs to be executed for different machining operations. Thus, the existing TW machines have been far removed from a full-automatic capability in processing a plurality of workpieces of different types required to acquire different prescribed contours.